Many implantable medical devices (IMDs) employed in a cardiac context gather or sense cardiac data, such as intracardiac electrogram (IEGM) data, to achieve their functionality. For instance, an IMD functioning as a pacemaker senses IEGM data. The IMD then analyzes the IEGM data to detect various parameters. Some IMDs employ various posture sensors, such as accelerometers, to provide information about a posture of the patient. The parameters and the posture information are utilized by IMD algorithms to effect pacing therapy and/or other cardiac conditions. IMDs by nature have finite processing resources and need to be ultra-reliable. Traditional posture sensors add an additional level of complexity to the IMD and hence a potential point of failure. Further, processing information from the posture sensors is resource intensive. In contrast, deriving additional information, such as posture information, from the sensed cardiac data would result in a relatively simpler IMD that utilizes a relatively lower amount of IMD resources.